Existing Internet performs networking and data transmission via TCP (Transmit Control Protocol)/IP (Internet Protocol). Two terminals connected to the Internet must have their respective IP addresses, so as to communicate with each other. However, due to the limited resources of the IP addresses, the operator cannot allocate a fixed IP address for each of end-users. Currently, the networking terminal is temporarily allocated an address using DHCP (Dynamic Host Configure Protocol). That is, when the user terminal is networking, one IP address is temporarily allocated by a DHCP server from an address pool to the networked terminal. The allocated IP addresses may be different each time the user terminal is networking. When the user terminal is off the network, the DHCP server allocates the address to other user terminal sequentially networked. This may effectively save IP addresses, which may ensure communication of the terminal user and may also improve usage of the IP addresses.
In the network using the TCP/IP protocol, each terminal must have at least one IP addresses to communicate with other terminal(s). But sometimes a situation may appear where a terminal has multiple IP addresses. As shown in FIG. 1, one client connects to a plurality of DHCP servers. The plurality of DHCP servers allocate IP addresses to the client, respectively. The client communicates with other terminals in different subnets by respective one of the plurality of DHCP servers. The DHCP server acts as a subnet gateway, and also has its own IP address subnet segment for allocating IP address to itself and its client connected thereto. Therefore, there may be a subnet IP address conflict existing between different DHCP servers. The solution for the IP address subnet conflict of the DHCP server in the prior art is only to modify the IP address subnet segment of the DHCP server manually. And, since the same batch of DHCP servers have the same factory settings, i.e. the same IP addresses and subnet masks, it is also required to configure the IP address of the DHCP server manually when the DHCP server is started up.